The local galaxy distribution does not violate the cosmological principle

Abstract

The cosmological principle, which states that the Universe is statistically homogeneous and isotropic on sufficiently large scales, is a foundational assumption of the standard cosmological model. A recent analysis of DESI DR1 galaxy samples reported coherent anisotropic features in the local galaxy distribution extending to gigaparsec scales. If correct, this result would directly contradict the cosmological principle and motivate inhomogeneous cosmologies. Here I analyze the same data and compare them with galaxy distributions predicted by the FLAMINGO cosmological hydrodynamic simulation, performed in the standard $Λ$CDM paradigm. I show that the apparent anomaly disappears when the correct comoving distance scale is used and when compared to mock catalogs that account for bias and redshift-space distortions. Rather than violating the cosmological principle, the observed structures are consistent with those expected in a $Λ$CDM Universe.